Times Tables 9x Strategy - Think One Less set of ten

This article is from the 10-article series "Times Tables" strategies. Tables are the strategies taught in the following: 2x, 5x and 10x, 3x, 4x, 1x, 0x, 11x and squares, 9x, 6x, 8x, 7x , 12x.

9x the facts at first sight seems to be difficult to learn the facts, since the size of the numbers. There are, however, for more examples found in the set of 9x simple facts make many different types of propagatingFacts.

9x teaching facts

Discuss with students what is special about the number nine. The fact that affected all its multiples, is that nine is one less than ten, this number is multiplied by the same number of tens, less than an identical number. Immediately, without further information, students should see that this is a way of working is a multiple of nine. For example, 9x5 = 5 tens - 5 items = 50-5 = 45

Other models that can be detected byThe students used for practice and 9x facts are as follows:

Multiples of nine straight years, writing a vertical column of numbers from 0 to 9, to insert a vertical column on the right side like 9 to 0. The result is the consequence of 09, 18, 27, 36, 45, 54, 63, 72, 81, 90 9x11 9x12 and should be treated separately as an extension of this model.
The sum of the digits in each multiple of nine is a multiple of 9 or 9 In other words, the figures of the first tenMultiples of nine are: 0 = 9 9 1 +8 = 9, 2 +7 = 9 3 +6 = 9 4 +5 = 9 5 +4 = 9 6 +3 = 9 7 +2 = 9, 8 +1 = 9 9 +0 = 9
The number of scores in a multiple of nine is always one less than the multiplier up to 9x10. For instance, 9x6 5 log (one less than 6), more than 8 orders of 9x9 (one in less than nine). This fact, together with the one described above can work for a multiple of nine years, up to 9x9. For example, 9x3 must have two orders (one less than three), two plus seven equals nine, so there are sevenones, so 9x3 = 27
A single "finger trick" can be used to show more than nine to 90. Keep both hands, palms outward. Think of each digit, numbered from left to right, 1-10 To multiply a number nine, finger press the corresponding number. For example, to show 9x8, put the eighth finger. The number of fingers on the left and right sides of the fingers showing the number of depressive scores and sequence: In this example there are seven fingers on the leftthe eighth and two fingers on the right, the answer to 9x8 is 72.

Resources

Presentation of 9x facts can be easily done using quality materials in which the grouping. For example, with dozens of frames allows a series of nine to find easily by 9 points on each frame. Discuss the number of counters: There are a series of ten or less the same number of them. For example, it is shown with ten frames 9x6 frames shows six of ten, with six pointsmissing or 60-6 = 54th

The trick of the fingers may be displayed on a poster on the classroom wall. This is a physical, kinesthetic strategy to save the facts that students often have 9x. The only disappointment is that it does not work for other groups of facts!

Next article

The next article in this series is "Times tables 6x strategy - Build five."